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Chemistry Questions and Answers August 31, 2020

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Iron exhibits +2 and +3 oxidation states. Which of the following statements about iron is incorrect? (a) Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds. (b) Ferrous oxide is more basic in nature than the ferric oxide. (c) Ferrous compounds are relatively more ionic than the corresponding ferric compounds. (d)

The atomic numbers of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionisation enthalpy (a) V (b) Cr (c) Mn (d) Fe

Knowing that the chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect (a) Because of the large size of the Ln(III) ions, the bonding in its compounds is predominantly ionic in character. (b ) The ionic sizes of Ln(III) decrease in general with increasing atomic number. (c) Ln(III)

Fusion of MnO2 along with KOH and O2 forms X. Electrolytic oxidation of X yields Y. X undergoes disproportionation reaction in acidic medium to MnO2 and Y. The manganese-containing ions present in W and X, respectively, are Y and Z. Correct statement(s) is(are). (a) Both Y and Z are coloured and have a tetrahedral shape (b) In an aqueous acidic

Consider the following reactions (unbalanced); Zn + hot conc. H2SO4 ? G + R + X Zn + conc. NaOH ? T + Q G + H2S + NH4OH ? Z (a precipitate) + X + Y Choose the correct option(s) (a) Z is dirty white in colour (b) Bond order of Q is 1 in its ground state (c) R is a V-shaped molecule (d) The oxidation state of Zn in T is + 1

The correct statement(s) about Cr2+ and Mn3+ is (are) [Atomic numbers of Cr = 24 and Mn = 25] (a) Cr2+ is a reducing agent (b) Mn3+ is an oxidizing agent (c) Both Cr2+ and Mn3+ exhibit da electronic configuration. (d) When Cr2+ is used as a reducing agent, the chromium ion attains d5 electronic configuration.

The pair(s) of reagents that yield paramagnetic species is/are (a) Na and excess of NH3 (b) K and excess of O2 (c) Cu and dilute HNO3 (d) O2 and 2-ethylanthraquinol

Copper becomes green when exposed to moist air for a long period. This is due to:- (a) the formation of a layer of cupric oxide on the surface of copper. (b) the formation of basic copper sulphate layer on the surface of the metal (c) the formation of a layer of cupric hydroxide on the surface of copper. (d) the formation of a layer of basic

one of the following exhibits the largest number of oxidation states (a) Mn(25) (b) V(23) (c) Cr (24) (d) Ti (22)

The type of isomerism present in nitro- pentamine chromium (III) chloride is (a) optical (b) linkage (c) ionization (d) polymerisation

How many expected signals are in H1-NMR spectra of n-butane A) 1 B) 2 C) 3 D) 4

Which of the following organic compound with molecular formula C3H C2 exhibits only one signal in the IH NMR spectrum a) 2, 2dichloropropane b) 1, 2dichloropropane c) 1, 3dichloropropane d) 1, 1dichloropropane

The ion that has sp d hybridization for the central atom, is A B C D IC1 IF6 IC14 BrF

The 1HNMR spectrum of CH3OCHCICHCl will exhibit a) A three proton doublet. One proton singlet and a two proton doublet b) A three proton singlet. One proton singlet and a two proton doublet c) A three proton singlet. One proton triplet and a two proton doublet d) A three proton triplet. One proton triplet and a two proton triplet

Which of the following has three types of hydrogens in the following compounds a) BrCHCH b) CH3 CH2 CH3 c) C6H5CH d) CH3CH2CH(CH3) NO

Which of the compound show only one signal is present in the PMR spectra a) C3H4, C3H6 b) C4H6, C5H12 c) C8H18, CH6O d) All of the mentioned

The distance between the centres of the peaks of doublet is called as a) Coupling constant b) Spin constant c) Spinspin coupling d) Chemical shift

What is the multiplicity of the methylene hydrogens of a carbon that is attached to a methyl group and to a methoxy group (a) doublet (b) singlet (c) quartet (d) triplet

How many signals would you expect to see in the H NMR spectrum of nbutane (a) 1 (b) 2 (c) 3 (d) 4

(a) 2 (b) 3 How many signals does 2,2,4trimethylpentane have in its H NMR spectrum,(c) 4 (d) 5

Which of the following compounds is frequently used as an internal reference in H NMR spectroscopy (a) TNS (b) DMF (c) TMS (d) DMSO

Which of the following describes the 1H NMR spectrum of 1,2dichloroethane (a) one doublet (b) two triplets (c) two doublets,(d) one singlet

Variables that can affect the efficiency and selectivity of adsorption include: (A) Temperature (B) Pressure (C) Adsorption isotherms (D) All of the above

Which of the following is NOT a condensation polymer Select one or more A. Neoprene B. Nylon 66 C. PHBV D. BunaN .

Determine total moles of ions in a solution made by diluting 50.0 mL of a 0.874 M solution of sodium carbonate to a total volume of 250.0 mL.

Determine the percent by weight of O in NaIO3. (Report your answer with three significant figures.)

The molecule known as MEHPPV is used in making a special kind of solar cell called an organic photovoltaic. When a 10.0 g sample of MEHPPV is combusted, it produced 28.7 g of CO and 9.13 g of HO. What is the empirical formula of MEHPPV

The valuable compound diborane, B2H6, can be made by the reaction 2 NaBH4 (s) 12 (s) B2H6 (g) 2 Nal(s) H2 (g) You use 1.203 g of NaBH4 and excess iodine. If you isolate 0.295 g of B2H6, what is the percentage yield of B2H6 from the reaction

One of the chief concerns of using carbonbased fuels is the release of the greenhouse gas CO into the atmosphere. It would be best to use a fuel that releases a lot of heat and the least amount of CO. Using enthalpy of combustions, determine which fuel, glucose (C6H1206) or octane (CsH1s), has a higher heat of reaction per mole of CO2 created. Use

Which transition would involve the emission of a photon with the longest wavelength Circle ONE a) E1 E3 b)E2 E3 c)E3 E1 d) E3 E2

Calculate the uncertainty in position of an electron moving at a speed of (1.50105 plus minus 1. x10) ms.,Is the uncertainty in position larger or smaller than the de Broglie wavelength of the electron Show your work.

Draw a Newman projection for the most and least stable conformations of 2,2 dibromo3,3dichlorobutane around the C2C3 bond. Calculate the difference in energy between these conformations using these data CICI eclipse strain 0.9 kcalmol BrBr eclipse strain 1.1 kcalmol ClBr eclipse strain 1.0 kcalmol methylmethyl eclipse strain 3.2 kcalmol methylCl

write the process and identification of any one organic compound containing N and s element

Write the theory and experimental process for determination of heat of neutralization of the strong acid and strong base.

Find out equivalent weight of ferrous ammonium sulfate and calculate the amount of ferrous ammonium sulfate for making N30 concentration solution

Name and identify the functional Group in Glucose

Write and explain the unit of heat of neutralization energy.

If NaOH is added to a solution of acetic acid A) H ions increases B) pH decreases C) CH3COO increases D) CH3COOH increases

Bond origin of transition molecule is observed at 19378 cm1 the rotational constant in exciated and ground states are 17522 cm1 (131) 1.6328 CMY (B). Estimate the position band width while a tower state has larger bond length. of

Electronic Spectra of Cl2 exists conversion, limit 487.5 nm, dissociation of Cl2 result into two chlorine atom, one of them in G.5, one is in E.S. which haning energy 011 er of an appropriate diagram. Estimate the dissociation energy of cla in KJ. mole, in its electronic G.93,

Rotational Raman spectra of H gas is found to be constant of series of stokes antistokes lines the first of which appears at 345.9 at 345 9 cm, to the relative source of exciation, calculate the bond bond length of length of H molecules.

Rotational vibrational frequency of H is 4395 cm1of mercury light ( 4358 A) is used as exciating radiation what would be wavelength of stakes antistakes lines in vibrational spectra of H.

for HBR force constant is G.13 x10 Nm. calculate frequency of radiation from transition 210 to 21, also calculate fundamental frequency KEVD point energy.

The rotational spectrum of Her shows two successive lines at 84.544 cmt. 101.355 cm, whed is the bandlength of HBr.

The rotational spectrum of Br79 F19 shows a series of equidistant lines with spacing of 0.71433 cm1. Find the bond length of the molecule,

Calculate force constant for hydrogen chloride molecule, as it shows absorption band at 289o cm1. Given At. wt. C 35,46, H1008 F 625201

The microwave spectrum of the CN radical shows a series of lines spaced at intervals of 3.798 cm1. what is the bond length of CN Griven At mass C 12.00 amu, N 14.00307 amu.

What is the value of B for H37 Cl if the rotational constant of H35 Cl is observed to be 10.590g cm

The fundamental vibrational band of c1 molecule is at 2940.8 cm1, where each chlorine atom has atomic weight 35.0 Determine the corresponding fundamental vibration band q c1 molecule in which the atomic weights of a atoms are 35.0 and 37.0 in the cla molecule, what to separation af spectral lineo due to isotopes

The option(s) with only amphoteric oxides is(are) A. Cr 2 O 3 , BeO, SnO, SnO 2 B. Cr 2 O 3 , CrO, SnO, PbO C. NO, B 2 O 3 , PbO, SnO 2 D. ZnO, Al 2 O 3 , PbO, PbO 2

What is the change in Gibbs Free Energy for a reaction that has an enthalpy change of 371.9 kJmol and a entropy change of 182.5 J(mol K) at 25.5 C Your Answer Answer units

The electronegativity of the following elements increases in the order (A) C, N, Si, P (B) N, Si, C, P (C) Si, P, C, N (D) P, Si, N, C

Atomic radii of fluorine and neon in Angstrom units are respectively given by: A. 0.72, 1.60 B. 1.60, 1.60 C. 0.72, 0.72

Consider the following reaction in aqueous solution 5Br (aq)BrO3(aq)6H(aq)3Br(aq)3HO(l)semantics If the rate of disappearance of Br (aq) at a particular moment during the reaction is 0.111 Ms, what is the rate of appearance of Br(aq) at that moment Your Answer Answer units

Identify the correct order of acidic strength of CO 2 , CuO, CaO, H 2 O. (A) CaO < CuO < H 2 O < CO 2 (B) H2O < CuO < CaO < CO 2 (C) CaO < H 2 O < CuO < CO 2 (D) H 2 O < CO 2 < CaO < CuO

KI in acetone, undergoes SN2 reaction with each of P, Q, R and S. The rates of the reaction vary as (a) P > Q > R > S (b) S > P > R > Q (c) P > R > Q > S (d) R > P > S > Q

1 (a) Two reagents that can be used to prepare chlorine gas are manganese (IV) oxide and concentrated hydrochloric acid. Write an equation for the reaction. Give the formula of another reagent that can be reacted with concentrated hydrochloric acid to produce chlorine gas. (1 mark) (iii) Describe how the chlorine gas could be dried in the

(a) (b) (c) Figure 3 shows the changes that take place between states of matter. Some of them have been Identified and others labelled. GAS (1) (ii) (iii) (i) (ii) Temperature (C) H Give the names of the processes I. II. 100 I H G Name one substance that can undergo process F when left in an open container in the laboratory.... 67 Figure 4 shows

Question 4 (a) The schematic diagram shows part of the Solvay process used for the manufacture of Sodium carbonate. ee (iii) Ammonia Carbon dioxide Saturated sodium chloride I. II. UNITI Process I Ammonium chloride Sodium hydrogen carbonate. UNIT II Explain how the sodium chloride required Two main reactions take place in UNIT 1. of ammonium

The boiling points of some compounds of hydrogen with some elements in Groups 4 and 6 of the periodic table are given below. (a) (d) Compound CH SIH Boiling point (C) 164.0 112.0 Compound HO HS Boiling point (C) 100.0 61.0 Which of the compounds CH4 and SiH, has the stronger intermolecular forces Explain why the boiling points of HO and HS show

Starting with 50 cm of 2.8 M sodium hydroxide, describe how a sample of pure sodium sulphate crystals can be prepared. (3 marks) In this question, candidates were required to describe an accurate step by step procedure which can be used to prepare a pure sample of sodium sulphate crystals starting with 50 cm of sodium hydroxide whose concentration

The structure of methanoic acid is L C 0H,What is the total number of electrons used for bonding in a molecule of methanoic acid Give reasons. In this question the candidates were required to state the number of electrons used in bonding in a molecule of methanoic acid.

1. During the Great Recession of 2007-2009, GDP was at times contracting at a 6% rate. In a recession: expansionary fiscal policy is countercyclical. contractionary fiscal policy is countercyclical. it is necessary for policymakers to wait for the economy to self-correct. attempts by the government to move the economy closer to full employment are

The accompanying data set contains five variables, x1, x2, x3, x4, and x5. Click here for the Excel Data File a. Subset the data set to include only x2, x3, and x4. How many missing values are there in these three variables Number of missing values b. Remove all observations that have Own as the value for x2. Then remove all observations that have